Third, if your ceiling is painted, like mine, get a long handled scraper and remove that top later. I'd suggest clipping the corners off the scraper. In my experience, straight corners tend to go into the ceiling very easily. Clipping off the pointed edge on each side seemed to lessen the chances of digging into the sheetrock. If your ceiling isn't painted, skip this step!

Fourth, get a sprayer, fill it with water, and spray a portion of the popcorn. Get it damp! If the popcorn doesn't change color, you aren't spraying enough. It should soak up the water and look darker. Don't spray a very large area and don't get what you do spray soaking wet.

Fifth, scrape the damp popcorn. It will come off in sheets. Unless you made it too wet. But then it will come off in muddy chunks.

Sixth and last, roll up the paper, taking the remains of your popcorn ceiling with you. The remaining mess should be minimal.

My buddy, Kim "Rockpile" Hall and I had a lot of success with this process. I'm planning on using it for the rest of the house, eventually. The remove-the-painted-layer portion was quite dusty, though! We looked like we'd been dipped in powdered sugar, afterwards.